Flexible and Contamination-Free Solutions
Air handling units equipped with run-around coil (RAC) systems provide an effective and hygienic method of heat recovery, particularly in applications where supply and exhaust air streams must remain completely separated. By transferring energy through a closed-loop water or glycol circuit, these systems ensure safe and flexible operation without any direct air mixing.
Our systems include anti-freeze protection on return air and anti-freeze glycol protection, with incorporated additional heating and/or cooling inputs.
Run-Around Coil Systems for the Highest Technical Requirements
A run-around coil system consists of two heat exchanger coils—one located in the exhaust air stream and the other in the supply air stream. These coils are connected by a closed piping loop filled with water or a water-glycol mixture. A circulation pump transfers thermal energy from the exhaust air to the incoming fresh air during the heating season, or removes heat from the supply air during warmer conditions. Because the two air streams never come into contact, this solution eliminates the risk of cross-contamination.
Such systems are ideal for applications with high technical requirements or where contamination must be strictly controlled. A frequency-regulated pump always ensures optimal medium flow for the highest heat recovery efficiency under different temperature regimes (supply, exhaust, or both) and/or different airflow conditions (supply, exhaust, or both).
Ideal for Hygienic and Sensitive Applications
The complete physical separation of airflows makes run-around coil systems particularly suitable for healthcare facilities, laboratories, pharmaceutical production, and industrial processes involving hazardous exhaust air, as well as environments where infection control or contamination prevention is critical.
Special high-efficiency counterflow coils are designed to provide optimal heat transfer between air and the heat transfer medium. Anti-freeze protection is ensured by sensors on the air or medium side.
RAC systems can also be used with an additional heat or cooling source to achieve the required supply air temperature. Standard sizes usually cover most requirements, but project-oriented solutions can also be provided.
Flexible Installation and Retrofit Advantages
One of the major advantages of run-around coil systems is installation flexibility. Since heat transfer occurs through piping rather than direct air contact, supply and exhaust units can be located far apart—on different rooftops, in separate plant rooms, or in buildings with complex duct routing.
This makes RAC systems an excellent choice for retrofit projects, where integrating a rotary or plate heat exchanger may not be feasible.